Effect of Humidity Variations in a Controlled Environment Chamber on Tear Evaporation After Dry Eye Therapy

Abstract

Pilot study-TER measurements required at least 10 minutes in the chamber to obtain a steady-state TER with no significant change to NITBUT. Study 1-TER has a reverse correlation with environmental humidity in the range of 5% to 70%, with TER reduced to zero at 70% RH. Dry eye subjects had a higher TER at all RH levels below 70%, and NITBUT is significantly different between DE and normal subjects at all humidities. Study 2-Emulsion-based drops reduced TER in DE patients by an amount equivalent to that obtained by raising environmental humidity by 30%. Noninvasive tear breakup time was improved in both normal and DE subjects at lower RH levels.

Clinical and Molecular Inflammatory Response in Sjögren Syndrome–Associated Dry Eye Patients Under Desiccating Stress

“…This finding agrees with previous studies [12][13][14][15] reporting that dry eye patients having diverse etiology can suffer ocular surface deterioration when exposed to desiccating conditions, which also occurs in healthy subjects. 14,30 Most of the dry eye tests tended to worsen in our study, showing significant deterioration in tear osmolarity, conjunctival hyperemia, and corneal staining ( Table 1).…”

“…1,2 With the aim of better understanding the disease and better showing dry eye therapeutics efficacy, customized instruments and facilities where environmental conditions can be controlled have been designed. [11][12][13][14][15] In the present study, we used our own facility (Controlled Environmental Research Laboratory) 13,25 and observed that the lacrimal functional unit status in SS dry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 López-Miguel et al -7 eye patients worsened after undergoing short-term desiccating conditions. This clinical deterioration was accompanied by significant changes in the activity of several tear molecules (IL-1RA, IL-6, IL-8, and MMP-9) previously reported to be elevated in patients with dry eye as compared to healthy subjects.…”

“…Therefore, our research group and others have studied the clinical and tear changes occurring in dry eye patients after exposing them to several desiccating conditions to evaluate how the lacrimal functional unit responds to a controlled adverse environment. [11][12][13][14][15] However, we were not able to find in the literature reports addressing the variation of tear molecules occurring only in SS-associated dry eye patients when being exposed to controlled adverse conditions in spite of the following two well-known facts: first, inflammation plays a major role in dry eye disease, 2 and second, concentrations of some tear molecules in severe dry eye patients are consistently different from healthy subjects. [16][17][18][19] The analysis of the changes occurring in tear molecules of SS dry eye patients could be interesting from a therapeutic viewpoint, 20 because this biochemical assessment could provide information regarding the mechanism of the acute exacerbations that these severe dry eye patients frequently suffer.…”

Discrepancy between subjectively reported symptoms and objectively measured clinical findings in dry eye: a population based analysis

“…Many DE patients are sensitive to adverse environments, where tear evaporation rates (TER) increase due to a reverse correlation when environmental humidity is in the range 5–70%. In fact, TER is reduced to zero at 70% relative humidity 20. Additionally, adult patients exhibiting mild-to-moderate DE and asymptomatic subjects of similar ages can both experience acute exacerbation of the disorder following exposure to a controlled desiccating environment (5% relative humidity) for 2 h 21.…”

Flow Evaporimeter To Assess Evaporative Resistance of Human Tear-Film Lipid Layer

“…Further, because the chamber is partially open to the environment, changes in environment lead to differing and uncontrolled results unless a complete environmental chamber is used. 10,54 Apparently, Cedarstaff and Tomlinson 56 were the first to employ a goggle evaporimeter with imposed flow. Their instrument supplied air humidified to 70% and parallel to contact-lens-covered eyes.…”